Valve Problems

[Mr. Tickle]

Hello Board!

We have in the past, had some ongoing problems with our CH system that have resulted in several call outs and unfixed solutions. Recently, a lot of this came to a head and i decided to try and get to the bottom of what was going on.

We have a Y system, cold storage tank in the loft, hot storage tank in the spare room next to the 3 Way valve + circulatory pump, a Glowworm Ultimate 30FF boiler, Danfoss CP15 programmer, room stat and 6 rads in total.

The house is about 12 or 13 years old an i wouldn't be suprised if the people that had it before us (4 years we've lived there) have done no maintenance.

We always had a problem where the heating wouldn't come on unless HW was needed, and sometimes never at all.

After a while, a plumber came out and replaced the motor in the valve controller unit and it worked perfectly for a long time.

While he was here, he suggested the pump would need replacing soon, before it karked it all together. THere's loads of built up limescale around the valves because of leaking joints.

So over the last 5 months, there's been more and more strange a'happenins and a'moanins from the rads/boiler/under the cupboard.

And then, it stopped.

It all stopped working and had gone kaput. I took a day off work and found out the pump had stopped working. I replaced the pump and the valves with new ones. I also replaced the rad in the upstairs bathroom as it had a tiny leak on the bottom.

While the system was drained off, i put some cleaner goop into the header tank. Before that i mopped the header tank out of the crap that was in there. I filled back up, opened all the valves on all the rads and ran it round for a day.

Then i shut off all but one rad and washed it round that for an hour, then alternated through all the rads in the house. After, i drained and filled and drained then refilled with some inhibitor.

Bled the system and it's all pretty much working well. Except for the valve thing.

I've taken the motor box unit off the valve and have been trying to operate it manually.

Can someone tell me if there is a standard for these things? I'm trying to imagine what it looks like inside to figure out the positions.

From that, i want to monitor the white box and see if that is working correctly. I suspect not, but it could be the programmer not sending the right signal to it, perhaps?

Why would the heating only be on when the HW is called for?

Programmer is asking for both CH + HW
Room stat is calling for CH
Tank stat is calling for HW
Pump is on, rads hot, tank pipes hot, tank temp increases.

As soon as the tank hits the right temperature, everything turns off. Straight away the pump stops and the valve moves.

Although, now it's not doing that.

Can someone tell me the correct sequence of priority or something to this system?

How should i try and tell if it's the motor in the valve or if it's the programmer not sending the right signal?

I should be able to have HW, HW+CH or just CH, right? Up till now, i've just been eeking up the tank stat, but water at 80o aint good!

Thanks for any help you can give me!

 

[seco services]

useally when the heating only works with the hw on then shuts down when hw satisfied is useally a faulty micro switch in the actuator not allowing power from the grey to the orange wire when only heating needed.

you've proved the motor in the actuator is working as your getting heating/hw.
if motor had failed you would never get heating even with hw on.

 

[Mr. Tickle]

Hey, thanks for your reply.

So, i should replace the micro switch in the unit? Or should i just buy a whole new unit?

Thanks.

 

[seco services]

do a test first to check.

put heating on only at programmer hw off.
wall stat calling.

white wire on valve will have power. ( the lever on the end of valve will be floopy)

grey wire will be live.
orange wire live.

if no power on the orange the the micro swith is faulty or the valve is not making contact fully.

 

[mogget]

Can you check voltages with a multimeter?

With the heating on (room stat calling for heat), and hot water off or cylinder stat satisfied, there should be 240v on the grey and white wires on the valve. If everything is working properly, the microswitch inside the valve should energise the orange wire and you should find 240v here as well.

 

[Tipper]

Get a replacement motorhead as fiddling about changing the motor is a waste of effort as it will always be unreliable afterwards particulalry as the aux. switches fail.

 

[mogget]

simultaneous posts

 

[Tipper]

Snap!

 

[D_Hailsham]

We always had a problem where the heating wouldn't come on unless HW was needed, and sometimes never at all.

After a while, a plumber came out and replaced the motor in the valve controller unit and it worked perfectly for a long time.

Did this cure the problem of heating only with HW?

Why would the heating only be on when the HW is called for?

Programmer is asking for both CH + HW
Room stat is calling for CH
Tank stat is calling for HW
Pump is on, rads hot, tank pipes hot, tank temp increases.

As soon as the tank hits the right temperature, everything turns off. Straight away the pump stops and the valve moves.
I should be able to have HW, HW+CH or just CH, right?

The Danfoss CP15 allows separate HW and heating so it sounds like a wiring problem.

First remove CP15 from wall plate and check the switch on the back is set to Pumped, not Gravity.

Is everything connected to a wiring centre (junction box)? Check that there is a wire from terminal 1 of the CP15 wall plate to the valve's Grey wire. There should also be a wire from the Cylinder thermostat "satisfied" terminal to the valve's Grey wire; i.e. three wires connected to cylinder stat.

 

[Mr. Tickle]

Thank you all for the detailed replies. I will check these over tomorrow.

FYI - changing the motor did work, but then it stopped again shortly afterwards. It is intermittent though. I cannot find it, but i kept a log of what was doing what, and it never stayed the same for long! Part of this was caused by a faulty gas solenoid in the boiler, which was half on/off. Obviously, that compounded the problem of fault finding. There is a thread on here about it somewhere.